Fluid governor or controller



March 5, 1968 R. H. THORNER FLUID GOVERNOR OR CONTROLLER Filed April 1,1966 INVENTOR. ROBERT H. THORNER United States Patent Ofi 3,371,574Patented Mar. 5, 1968 ice 3,371,674 FLUID GOVERNOR R CONTROLLER RobertH. Thorner, 8750 W. Chicago Blvd., Office F, Detroit, Mich. 48204Continuation-impart of application Ser. No. 463,319,

June 11, 1965. This application April 1, 1966, Ser.

12 Claims. (Cl. 137-36) This invention relates to a fluid control devicefor automatically regulating any controlled condition, such as agovernor device for controlling the speed of an internal combustionengine or other machine having rotating means to be controlled. Thepresent application is a continuation-in-part of application Ser. 'No.463,319, filed June 11, 1965, now Patent No. 3,257,914, which in turnwas a continuation of my application Ser. No. 238,575, filed Nov. 19,1962 entitled, Fluid Governor or Controller" (now abandoned) which was acontinuation-in-part of my application Ser. No. 687,241, filed Sept. 30,1957, now Patent No. 3,092,084 and Ser. No. 815,177, filed May 22, 1959,now Patent 3,068,849.

Governors currently in use for precisely controlling the speed of aprime mover, such as a diesel engine, are mostly of the servo-mechanismtype having oil powered servo-motor controlled by a pilot valve actuatedby a centrifugal fiyweight mechanism. The pilot valve usually comprisesa spool slidable in a bore to cover or uncover ports that directpressure oil from a source to the servomotor and/or permits oil to drainfrom the servo-motor as required in normal speed regulating movements.For precision or isochronous governors (constant speed at all loads),the presently known devices provide a pilot valve action in Which thevalve must always be in a fixed or neutral axial position to hold agiven set speed; and for changes in speed the pilot valve must deviateor make excursions away from its neutral position to provideintermittent fluid forces on the servomotor tending to restore thespeed, whereupon the pilot valve returns to its neutral position. Withthis type of controller system, a speeder-spring. balances the pilotvalve position against the centrifugal force of the flyweights or otherspeed-responsive means. Since the system is balanced in only one axialposition which occurs at only one force of the speeder spring for a setposition of the speeder-spring-control-lever, the flyweights willbalance this force at only one speed. Hence, the governor is inherentlyisochronous at each position of the speederspring-control lever, butprovides a different isochronous speed at each different position of thecontrol lever.

The governor described thus far, although isochronous, also tends to beinherently unstable for several reasons. Firstly, the pilot valvesconventionally used are nonmodulating and produce a sudden increase inpressure on the servo-motor when the pilot valve moves away from itsbalanced neutral position. This action causes the servomotor to getahead of the movement of the pilot valve or to over-control the enginewhich produces surging. Secondary, this over-control is made worsebecause of the relatively large mass of the pilot valve and fiyweights,which mass affects the speed of response of the elements and thus thecorrecting return movement to catch the servo-motor in time to preventexcessive over-control. But, thirdly, one of the most important factorscontributing to such over-control of the servomotor is the static anddynamic friction in the flyweight and pilot valve, as well as itscompensating system, which cause minute delays in the speed-correctingaction thereof.

In present governors the inherent instability above described isovercome by the addition of compensating systems. These systems usuallycomprise a piston operated by the servo-motor toapply a temporary oilpressure (by bleeding trapped oil) acting on another piston connecteddirectly or through a spring to either the pilot valve itself, or to anaxially-movable sleeve having ports cooperating with the pilot valve, orto a lever connected to the pilot valve, all in a manner well known tothose skilled in the art. The action is such that when the pilot valvedeviates from its neutral position and the servopiston first moves torestore the engine speed, an oil pressure is produced (on the pilotvalve or its sleeve) to instantly return the pilot valve to a neutralposition in relation to its sleeve which stops further movement of theservo-motor. An adjustable delay bleed is provided to permit thistemporary pressure to dissipate; then the pilot valve can deviate againfrom its neutral position to cause another step movement of theservo-motor, and so on, until the speed is corrected. This action causesthe servo-motor to move in fast incremental steps, to preventover-control, and stability is achieved since in in each step atemporary speed droop is produced. To set the governor initially, theopening of the delay bleed is increased until the engine surges and isthen closed sufficiently to stop the surging.

Such compensating systems have several undesirable characteristics. Theabove descrbied compensating step action tends to slow down the movementof the servomotor and thus causes a speed deviation with a sudden changein load. The more the delay bleed must be closed, the slower will be theservo-motor action and the greater will be the speed deviation producedwith a sudden change in load. It is recognized that the lower the massand friction of the pilot valve and fiyweight, the less compensation isnecessary and as a result the delay bleed need not be so restrictive. Tothis end, present governors have their pilot valves, fiyweights,compensating pistons or sleeves, etc., made of hardened precision-groundmaterials with anti-friction bearings used freely throughout. Also, inmany instances the pilot valves and compensating pistons, or sleeves aremechanically rotated by added driving mechanism in an attempt to reducefriction. These expedients do not eliminate the problems but merelyreduce their effect. The pilot valves and compensating pistons ofconventional governors have clearances measured in ten-thousandths of aninch, and their rotation not only requires complex and costly addedmechanism but still are subjected to the surface tension of the oil inspeed-responsive movements. Much Worse, one of the main problems of suchhydraulic governors is the deposit of gum or dirt particles which formbetween the close-fitting surfaces of the pilot valve or compensatingpiston and their respective sleeves, thereby making the movement of theparts somewhat erratic and reducing the reliability of the governors.

Substantially the same problems exist in the regulation of othercontrolled conditions, such as temperature, velocity, pressure, positionof a member, etc., and the same expedients used for the improvement andrefinement of speed governors are used in such other closed loop controldevices.

In another type of fluid controller in which the pilot valve modulatesthe pressure directed to a single-acting servo-motor and is biased by aspeeder spring, a permanent speed droop is inherently produced in stablegovernor operation. Such governors are inherently unstable atisochronous operation. In my governor devices of this type, I have beenable to provide isochronous operation by including in this combination are-set means (such as a spring) operated as a function of the positionof the control member. Examples of my governors of this type which arecapable of stable isochronous operation are shown in FIG. 8 of my saidco-pending application Ser. No. 687,241 and in Ser. No. 815,177, andalso in my Patent No. 2,887,998 issued May 26, 1959. While thesegovernors represent a substantial improvement in the art primarilybecause of their frictionless characteristics and low cost, if the speeddroop is reversed (lower speed at lower loads) in any portion of theloading curve, the governors become unstable in this portion. Thus, myprevious governors above discussed have desirably improved the limit ofstability from a forward speed droop (such as A-G in FIG. 2) toisochronism (A-D). These governors primarily are intended for automotiveuse in which cost is highly critical. The governor of the presentinvention will usually be utilized in applications requiring closerregulation although the cost is somewhat higher, or would be used forstationary, marine, or railroad engines, gas turbines, atomic engines,etc.; or as any precise controller for regulating any controlledcondition such as temperature, pressure, velocity, humidity, etc.

A main object of the present invention is to provide a speed governor,or other control apparatus to regulate any controlled condition, inwhich means are provided to produce stability with all speed droops,including reverse speed droops (A-E in FIG. 2), thereby to providesubstantially a surgeless governor or controller.

All governors or similar controllers, even when considered stable, areconstantly moving back and forth slightly to maintain the controlledcondition. The better and smoother the governor or controller, thesmaller will be these minute oscillations. My governors above discussedare so fast in responding to the speed-change signal, that theseundesirable effects are negligible. A second object of the presentinvention is to provide a speed governor, or other control apparatus toregulate any controlled condition, in which means are provided tosubstantially reduce the amount which the (engine) control memberdeviates from a desired position during stable operation of thegovernor, thereby providing a very smooth engine operation when thegovernor is stable.

Further objects and advantages of the invention will be apparent fromthe following description, taken in connection with the appendeddrawings in which FIG. 1 is a diagrammatic view of the governorembodying the present invention and FIG. 2 is a reference chart.

While the present invention is described with reference to itsapplication on an internal combustion engine as a governor regulatingthe speed thereof, it will be understood that the invention is notlimited thereto, and that it is fully applicable to other installationssuch as for gas engines, steam engines, or gas turbines, etc. Myimproved governor or controller may also be used for regulating otherdevices in response to speed, or in response to any controlledcondition, as will be described.

In the drawings there is shown by way of example one form of governingmechanism embodying the present invention. Referring to FIG. 1, thegovernor is illustrated as including an input shaft 12 operativelyconnected to and driven by an element (not shown) rotating as a functionof the speed of an engine or machine (not shown). An output shaft 14 ofthe governor is 0peratively connected to transmit axial movements of theshaft to regulate the control member, which in the example showncomprises a throttle 16 to regulate the flow of air to the engine in apassage 18.

The governor includes means to produce a force varying as a function ofthe rotary speed of an element of the engine. In the example illustratedin FIG. 1, a frictionless centrifugal flyweight device 20 of the typedisclosed in my said co-pending application, Ser. No. 687,241 is shown.This flyweight device comprises a base member 22, either secured to ormade as a part of the shaft 12, which has suitably secured thereto apair of leaf springs 24. The leaf springs 24 carry a pair of flyweights26 which are joined by a frictionless flexible strip or string-likematerial such as a piece of spring (music) wire 28 of generally U-shapesuitably secured to the 1 weights. The wire has secured thereto at itscentral portron a force-transmitting cup 30 having a cylindrical borefor rotation about a rod or cylindrical shaft 32. The shaft isconstrained from rotation by leaf spring means to be described and has arounded or pivot end for abutting contact with the bottom or end of thebore of cup 30. Rotation of shaft 12 causes weights 26 to produce aforce and move radially outward to impart a rightward force on (andmovement of) the cup 30 tending to move shaft 32 axially in a rightwarddirection, all as viewed in FIG. 1. The bending action of the leafsprings 24 and wire 28 is frictionless; also any eccentricity ormisalignment of shaft 32 with respect to shaft 12 is accommodated bylongitudinal and torsional bending of wire 28. In this manner, theproduction and transmission of axial forces and movements to the shaft32 is accomplished without friction irrespective of productionvariations. A more detailed explanation of this flyweight mechanism ismade in my said co-pending application, Ser. No. 687,241.

The rod or shaft 32 is suitably secured, as by pressing or soldering toa pilot valve 34, and is carried thereby. The pilot valve is supportedfor frictionless axial swingable movements by a pair of spacedsubstantially parallel leaf springs 36 and 38 suitably secured at oneend thereof to a portion of the governor housing, as by screws. The freeends of both leaf springs are secured to the pilot valve as shown inFIG. 1 by suitable means, as by pressing or soldering, all as disclosedin more detail in my said co-pending application, Ser. No. 687,241.

The main body of the pilot valve is suspended by leaf springs 36 and 38within a chamber 42. The valve body includes a pair of conical faces forcooperating with a fluid inlet orifice 44 and a fluid outlet orifice 46to form two variable restrictions, so that chamber 42 is provided withoppositely varying inlet and outlet restrictions, or valves.

Any fluid may be used in the governor of the present invention, so thatthe instrument will operate satisfactorily with either air or liquidunder pressure (or vacuum) supplied to the pilot valve. Accordingly, itis to be understood that when the term pressure fluid circuit or justfluid circuit is used herein, it refers either to liquid or gas underpositive or negative (vacuum) pressure.

In FIG. 1, by way of example, liquid such as oil is supplied by aconventional gear pump 48 having the usual by-pass conduit and reliefvalve (not shown) to maintain a substantially constant pressure at thepump outlet. The pump is fed fluid such as oil from a reservoir 50through an inlet conduit 51. The outlet of the pump is transmittedthrough a conduit 52 to a pressure regulator mechanism 53 which acts tomaintain a constant pressure at the inlet orifice 44, which constantpressure varies as a function of the position of throttle 16. In theform shown, the regulator mechanism comprises a valve 54 operated by apressure responsive member such as a diaphragm 55 biased by a spring,56. Diaphragm 55 forms an atmospheric pressure chamber 57 (ventedthrough port 57a) and a pressure chamber 58. A spring retainer 59 isactuated by a link 60 which is operated by throttle linkage 14 toincrease the force of spring 56 as the throttle closes, and conversely.A conduit 62 transmits the pressureregulated fluid from chamber 58 tochamber 64 without restrict on, by making the conduit large enough topreclude line loss; in this manner, the regulator always controls thepressure at orifice 44. At any position of throttle 16, 1f the pressuretends to increase in chamber 58 for any reason, diaphragm 55 reduces theopening of valve 54 to restore the original pressure set by spring 56and conversely. Similarly, at different throttle positions, a differentconstant pressure is maintained to balance the changed force of spring56. The flow of fluid through the governor circuit is as follows: thefluid flows from pump 48 past valve 54, through the conduit 62 throughinlet chamber 64, past orifice 44, through chamber 42, past orifice 46,into atmospheric outlet chamber 66 and through return conduit 68 toreservoir 50. When the pilot valve moves rightwardly, as viewed in FIG.1, the aperture of orifice 44 gradually reduces while the aperture oforifice 46 gradually increases, which action causes the pressure inchamber 42 gradually to decrease. A leftward movement of the pilot valvecauses a reverse action which efiects an increase of pressure in chamber42.

The governor output shaft 14 is actuated by a servounotor 70 comprisinga piston 72 axially slidable in a cylinder 74 and biased in athrottle-closing direction by a servo-poWer-spring 76. One side of thepiston 72 is exposed to atmospheric pressure in a chamber 78 whichcommunicates with conduit 68 through a conduit 79. The right side ofpiston 72 is exposed to modulated fluid pressure in a chamber 80 whichcommunicates through a conduit 82 with chamber 42. Thus, the pressureexisting in chamber 42 are statically transmitted to chamber 80 toeffect a desired movement of piston 72. Hence, a rightward movement ofthe pilot valve reduces pressure in chamber 80 to enable spring 76 toreduce the opening of throttle 16. A leftward movement of the pilotvalve increases pressure in chamber 80 to overpower spring 76 whichincreases the-throttle opening.

A disk 84 is carried by the pilot valve shaft and disposed within acylinder 86 to provide a diametrical or perimetrical clearance of about.003-. ()5", for example, with respect to the cylinder. The diskbalances the area of the pilot valve exposed to the pressure in chamber64 in a predetermined manner so that the pressure variations in chamber64 do not adversely affect the operation of the governor. The disk mayprovide another useful purpose to be discussed hereinafter. The diskclearance is provided to maintain the frictionless characteristics ofthe entire speed-sensing mechanism; a slight bleed of fluid past thedisk into atmospheric chamber 88 and to drain is necessary to achievethis frictionless operation.

Speeder spring means are provided to act on the pilot valve to bias theforces of the flyweight device. In the form shown in FIG. 1, a spiral orclock-type spring 90 acts without friction on a pointed or pivot end ofthe pilot valve. A shaft 92 supports the spiral spring which is rotatedto wind and unwind" by any suitable means, as by a manually operatedlever 94 for example.

The leaf springs 24, 36 and 38 as well as the clock spring 90 and wire28 may be made of any spring material such as stainless steel, orPhosphor bronze. For best fatigue resistance beryllium-copper isdesirable. For the supporting leaf springs, any other sheet materialhaving consistent elasticity may also be used. Strips of such stock havevery small resistance to bending perpendicularly to their plane butoffer very high resistance to bending within their plane, and moreimportant, are consistent in their action so they are frictionless inoperation. Any of the V-type or cross-type leaf springs disclosed in myPatent No. 2,808,042, issued Oct. 1, 1957, and in my said co-pendingapplication Ser. No. 687,241 may be used in place of the supporting leafsprings disclosed herein. The clock spring 90 or any or all of the leafsprings 24, 36 and 38 may be of bi-metal to compensate for any errorsproduced by changes in the temperature of the oil or in the springforces of the speeder spring.

In the specification and claims herein, all supporting leaf springs andwires associated with the pilot valve, fiyweight, compensation system,or Speeder spring are referred to as substantially frictionless. Thesespring elements actually are completely frictionless from a practicalstandpoint, since in extensive tests of the pilot-valveaction by itselfwhen supported by leaf springs, no lag or hysteresis could be measuredthat wouid affect the governing action. Any intermolecular friction inthe material itself can, of course, be disregarded, since it isimmeasurably small. The term substantially has been used solely inrecognition of this minute intermolecular friction.

Now consider the action of the governor described thus far, which wouldbe the same construction and operation as disclosed in FIG. of my PatentNo. 2,808,042,

issued Oct. 1, 1957. Assuming the governor operating in a stablecondition, if the speed increases, the flyweights 26 move radiallyoutward so that wire 28 moves cup 30, shaft 32, and pilot valve 34 tothe right. Such movement, as above described causes the pressure inchambers 42 and to decrease which enables spring 76 to move throttle 16in a closing direction tending to restore the governed speed. When thespeed decreases from the governed value, the reverse action is producedtending to open throttle 16.

The governor, as described thus far, must produce a normal or forwardspeed-droop (such as 4-7 percent) in order to be stable, as shown by AGin FIG. 2. The position-type pilot valve shown in FIG. 1 must move to(and stay at) new positions as a function of speed in order to effect acorresponding movement of the throttle. This is true because the forceof spring increases slightly as the pilot valve moves to the right inorder to produce the variable pressures on only one side of the piston72 to re-position the piston and balance the varying forces ofpower-spring 76 in this single acting servomotor. Thus the pilot valveaction is not of the excursion type as disclosed in FIG. 1 of my PatentNo. 3,051,139, issued Aug. 28, 1962; in this governor the pilot meansmakes excursions from and back to a mid-position to effect stepmovements of a double acting servo-motor as described in this patent.FIG. 2 shows a power curve RAS at wide-open-throttle of HP. and r.p.m.

vAs above discussed, the sin le acting servo-t e governor of the presentinvention will not be stable at a speed droop less than a predeterminedamount, such for example as 2-4 percent, and which will be'referred tohereinafter as the critical speed-droop beyond the limit of stability.This is shown by A-G in FIG. 2.

Now consider the governor with re-set means added which apply forcesacting on the pilot valve 34 as a function of the position of thecontrol means. In the example shown in FIG. 1, a re-set spring 96 isillustrated which increases the total rightward force on the pilot valveas the throttle closes, and conversely. For the present, consider thespring 96 as directly operated by the piston 72, and the intermediatemechanism shown in FIG. 1 will be discussed hereinafter. The governor,as now assumed, is substantially the same as disclosed in FIG. 8

of my said co-pending application, Ser. No. 687,241. I have found thatthis combination of elements (a singleacting servo-motor with aspring-biased modulating pilot valve and a re-set spring) substantiallyimproves the limit of stability. The critical speed-droop is nownegative or at least some droop less than zero, since this governorcombination can be calibrated to be completely stable at isochronousoperation (zero droop), as shown by the loading curve A-D in FIG. 2.

The present invention improves the governor operation by addin to thecombination, above discussed, a timedelay mechanism ltitl between there-set spring 96 and a shaft 98 connected to piston 72. In thetime-delay means illustrated in FIG. 1, a pair of flexible diaphragms101 and 192 enclose chambers 134 and 106, respectively, formed by a wall108 of a housing 110. A small orifice 112 connects the two chamberswhich are entirely filled with a fluid, such as a liquid. The re-setspring 96 is operatively connected to diaphragm 101. A coil delayspring114 is secured at one end to a retainer 116 connected to diaphragm 102and at its other end is secured to a retainer 118 which is part of shaft98. The delay spring 114 is of low force compared to power spring 76.The re-set spring is also of low force, preferably much lower than theforce of the delay spring 114.

The operation of the present governor inventive combination is asfollows. When the speed increases above the governed value, flyweight 20moves pilot valve 34 to the right to move throttle 16 in a closingdirection, as above described. This action stretches spring 114 andapplies a rightward force on diaphragmItlZ. Because of the restrictiveeffect of orifice 112, liquid gradually moves from chamber 104 to 106 sothat the rightward movement of diaphragm 101 and extension of re-sctspring 96 is caused to delay or lag behind the movement of the controlmeans, throttle 16. The amount of delay or lag is determined by the sizeof orifice 112, a smaller orifice providing a greater lag. Aftersufficient oil has transferred from chamber 164 to 106 to equalize thepressures in chambers 104 and 106, the full calibrated re-set force ofspring 96 will have been attained corresponding to the position ofthrottle 16. In this action, as previously discussed, the re-set springeffects a further rightward movement of pilot valve 34 which effects amore closed position of throttle 16 than without the re-set spring.However, with this construction, the force and rate of spring 96 can beselected to cause the throttle to settle at a position providing agoverned speed less than the original governed speed prior to thespeed-increase, thus producing a reverse or negative speed droop, asshown by the loading curve A-E in FIG. 2.

Because of the action of the time delay mechanism, the governor iscompletely stable at this reverse speed droop. This is true because thedelay mechanism 100 causes the re-set action of spring 96 to lag behindthe movement of control means 16 sufficiently so it can, in effect,first stabilize at a positive (or zero) droop, which is stable as abovediscussed, and then secondly it is reset to a lower speed. The actioncan be better understood by again considering the governor without there-set spring, as above discussed, in which the droop would be positivewith a speed increase as the load decreases to provide stable operation.Then assume that the force of speeder spring 90 is manually reducedsufficiently to reduce the stable governed speed below the initial speedat the higher load; this same action is produced by the delay mechanism100 and re-set spring 96. When the speed decreases from the governedvalue, the reverse action occurs; flyweight 20 moves pilot valve 34leftward to effect an opening of throttle 16 which compresses spring114, and re-set spring 96 is retracted with a lag due to the reverseaction of the delay mechanism. This action causes the stable governedspeed to be higher than the original speed at the initial lower load(reverse droop) along curve E-A in FIG. 2.

Thus, by properly selecting the size of orifice 112 of the relaymechanism there is no limit of stability, and because of this mechanismthe governor is in effect truly surgeless. One highly useful result ofthis construction is that when the governor is setfor isochronousoperation, production units would never cause surging if a slightreverse droop is produced in view of production variations. Thus thegovernor is not critical and can be calibrated if desired with limits ofplus or minus a desired isochronous loading curve, such as A-D of FIG.2. Also, a stable reverse droop is often required, such as in certainmotor generator sets.

In any speed regulating mechanism, or similar closedloop control device,it is highly desirable that the friction of all the elements which movein response to speed (and other elements that act thereon) be minimized,or at best entirely eliminated. The total of all these elements thatmove together in response to speed-changes might be termed the speedsensing mechanism, and in the control device of the present inventionare frictionless in their speed-responsive movements, including alltheir connections. These elements of the speed-sensing mechanism of thepresent invention are the leaf springs 24, weights 26, wire 28, shaft32, pilot valve 34 and its supporting springs 36 and 38, clock spring90, re-set spring 96, diaphragms 101, 102 and spring 114. Because of thefrictionless character and low mass of these elements in theircooperative action, the sensing movements of the flyweights and pilotvalve and the compensating movements acting thereon are extremely fastand, more important, consistent with no measurable lag. Hence the speeddeviation accompanying a change in load is much less than forconventional governors of this type. This characteristic is furtherenhanced by the modulating nature of the pilot valve in which thepressure differential across the piston 72 gradually changes as thepilot valve gradually is moved, thus reducing the tendency forover-control. Equally important, none of the elements of the sensingmechanism of my governor, such as the pilot valve and compensating disk84 require close fits against mating sliding surfaces. Hence, gum anddirt cannot wedge progressively in the clearances between these surfacesto cause mal-functioning of the governor. This is particularlysignificant as the governor may be stable when placed in service butbecomes unstable as dirt or gum wedges progressively between thesesurfaces. In my governor the clearances around the pilot valve body canbe very large, such as A" radially, and the clearance around the diskmay be large, such as .003.005 diametrically. Because of the completeelimination of all close-fits in the sensing mechanism of my governor,its reliability and life are greatly improved over conventionalgovernors.

The governor as described thus far is not only inherently stable but,because of the frictionless characteristics and low inertia is verysmooth. But even greater smoothness can be achieved by providing in theinventive combination pressure regulator means 53 to change the pressureof the source fluid flowing to the pilot valve as a function of theposition of the throttle in such manner tending to reverse the throttle.In the example illustrated in FIG. 1 and described above, the pressureregulator 53 controlled by link 60 causes the pressure in chamber 64 toincrease as the throttle 16 closes, and conversely. The improvedstabilizing action of this construction is as follows: At anyinstantaneous fixed position of the pilot valve (in the sense that thepilot valve movement is a series of instantaneous fixed positions), ifthrottle 16 tends to close for any reason, the action of pressureregulator 53 increases the pressure in conduit 62 and chamber 64, whichcorrespondingly increases the pressure in chambers 42 and thereby movingpiston 72 to return throttle 16 to its original position. If thethrottle tends to open at any instantaneous fixed position of the pilotvalve for any reason, the reverse stabilizing action is produced. At adifferent instantaneous fixed position of the pilot valve, the throttlewill stabilize in the same manner at a different position. In a sense,this throttle-stabilizing action at instantaneous fixed positions of thepilot valve provides a second pressure-regulating action in thegovernor. As the throttle deviates in either direction, it operatesregulator 53 to maintain constant the pressure in chamber 80 andstabilizing the throttle in the process.

For this throttle-stabilizing concept, in the form shown, the disk 84compensates for the effects of the variations of pressure in chamber 64acting at orifice 44 on the exposed face of the pilot valve 34, aspreviously described. For example, the disk 84 can be used to providere-set action in place of the spring 96 and delay mechanism 100 byhaving the area of disk 84 larger than the exposed area of the pilotvalve. Then, when the speed increases to effect rightward movement ofthe pilot valve to reduce the opening of throttle 16, the correspondingincrease in pressure in chamber 64 acts on disk 84; since in thisexample the disk area is larger than the area of the pilot valve, thelatter is moved more to the right resulting in a further closure of thethrottle. While this construction is simpler and, presumably, lessexpensive than the spring and timedelay re-set means, it is stable onlyat isochronous operation and forward speed droops.

It is important to appreciate that while the throttlestabilizingconstruction of pressure regulator 53 and link 60 enhances the re-setand time-delay mechanism, and conversely, neither is essential to theother. But the entire combination as disclosed in FIG. 1 provides anextremely smooth and substantially surgeless governor. It is alsoimportant to appreciate that the time-delay mechanism and re-set springcan operate with any position-type 9, controller, such as with adirect-acting mechanical-centrifugal speed governor, for example.

Any other type of sensing means to produce forces as a function of speedmay be employed in the present invention Without changing the scopethereof. It is highly desirable, however, that the means producingforces acting on the pilot valve be frictionless, as is the flyweightshown in FIG. 1. In addition, the controller principles disclosed hereinmay be employed equally well with frictionless sensing means to regulateany other controlled condition, such as temperature, pressure, humidity,position of a member, liquid level, altitude (such as an airplane,missile or space vehicle), velocity of fluids, viscosity, acceleration,altitude, or any other condition to be controlled.

What is claimed is:

1. In a self-regulating control mechanism for automatically controllinga variable condition the combination of, control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of pressure fluid to produce a flow of fluid therethrough andcommunicating with said pressure responsive member, valve'means in saidcircuit for controlling pressure therein acting on said presureresponsive member for effecting regulating movements thereof, sensingmeans responsive to changes in the controlled condition to produceforces varying as a function thereof and acting on said valve means toeffect movements thereof for causing saidcontrolled-condition-regulating movements of said pressure responsivemember and said control means, and pressure-controlling means includingpressure regulator means operatively associated With said control meansto vary the magnitude of said source-pressure as a function of themovement of said control means and tending to correspondingly vary saidpressure controlled by said valve means in a direction tending .toreverse the movement of said pressure responsive member and said controlmeans.

2. In a self-regulating control mechanism for automatically controllinga variable condition the combination of, control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of pressure fluid to produce a flow of fluid therethrough andcommunicating with said pressure responsive member on one side thereof,valve means in said circuit for controlling pressure therein acting onlyon said one side of said pressure responsive memberfor effectingregulating movements thereof, first variable force biasing meansopposing the forces of said pressure responsive member produced by saidlast-named pressure acting thereon, sensing means responsive to changesin the controlled condition to produce forces varying as a functionthereof and acting on said valve means to effect movements thereof forcausing said controlled-conditionregulating movements of said pressureresponsive member and said control means, second variable force biasingmeans acting on said valve means with a force varying as a functionthereof for establishing the operating position of said valve means toestablish the desired value of said controlled condition, andpressure-controlling means including pressure regulator meansoperatively associated with said control means to vary the magnitude ofsaid source-pressure as a function of the movement of said control meansand tending to correspondingly vary said pressure controlled by saidvalve means in a direction tending toreverse the movement of saidpressure responsive member and said control means.

3. In a self-regulating control mechanism for automatically controllinga variable condition the combination of, control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of pressure fluid to produce a flow of fluid therethrough andcommunicating with said pressure responsive member on one side thereof,valve means including a movable valve member in said circuit forcontrolling pressure therein acting only on said one side of saidpressure responsive member for effecting regulating movements thereof,the configuration of said valve memher in relation to other elements ofsaid valve means adapted to produce modulated pressures acting on saidpressure responsive member to effect movements thereof as a function ofthe position of said valve member, first biasing means acting on saidpressure responsive member with a force varying as a function of theposition thereof to oppose the forces produced thereon by saidlast-named pressure, sensing means responsive to changes in thecontrolled condition to produce forces varying as a function thereof andacting on said valve means to effect movements thereof for causing saidcontrolled-conditionregulating movements of said pressure responsivemember and said control means, second variable force biasing meansacting on said valve means with a force varying as a function thereoffor establishing the operating position of said valve means to establishthe desired value of said controlled condition, and pressure-regulatormeans including a diaphragm exposed to said source pressure andoperatively associated with said control means to vary the magnitude ofsaid source-pressure as a function of the movement of said control meansand tending to correspondingly vary said pressure controlled by saidvalve means in a direction tending to reverse the movement of saidcontrol means.

4. In a self-regulating control mechanism for automatically controllinga variable condition the combination of, control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of pressure fluid to produce a flow of fluid therethrough andcommunicating with said pressure responsive member on one side thereof,t'wo restrictions in said circuit, said pressure responsive membercommunicating with said circuit at a point between said tworestrictions, valve means in said circuit for controlling pressuretherein acting only on said one side of said pressure responsive memberfor eifecting regulating movements thereof, said valve means including amovable valve member in said circuit to vary the restrictive elfect ofat least one of said two restrictions for modulating the pressure insaid circuit between said two restrictions transmitted to said one sideof said pressure responsive member for effecting movements thereof 'as afunction of the position of said valve member, first biasing meansacting on said pressure responsive member with a force varying as afunction of the position thereof to oppose the forces produced thereonby said last-named pressure, sensing means responsive to changes in thecontrolled condition to produce forces varying as a function thereof andacting on said valve means to effect movements thereof for causing saidcontrolled-condition-regulating movements of said pressure responsivemember and said control means, second variable force biasing meansacting on said valve means with a force varying as 'a function thereoffor establishing the operating position of said valve means to establishthe desired value of said controlled condition, and pressure-regulatormeans operatively associated with said control means to regulate saidsource-pressure at predetermined values varying as a function of theposition of said control means and tending to correspondingly vary saidpressure controlled by said valve means in a direction tending toreverse the movement of said control means, said pressure regulatormeans including means to maintain said source pressure under allconditions at one said predetermined value corresponding to one definiteposition of said control means and at another said predetermined valuecorresponding to another definite position of said control means underall conditions, and so on.

5. In a self-regulating control mechanism for automatically controllinga variable condition, the combination of, control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of varying fluid pressure to produce a flow of fluid therethroughand communicating with said pressure responsive member, a restriction insaid circuit exposed to said varying source pressure, valve meansincluding a movable valve member in said circuit cooperating with saidrestriction for controlling pressure therein acting on said pressureresponsive member for effecting movements thereof, said valve memberhaving a portion exposed to said varying pressure and tending to beaffected by changes in fluid force produced on said valve portion byvariation in said source pressure, sensing means responsive to changesin said controlled condition and providing forces acting on said valvemember to effect movements thereof for producingcontrolledcondition-regulatin-g movements of said pressure responsivemember and said control means, a fluid chamber having an aperturetherein, a pressure sensitive member associated with said valve memberto apply forces acting thereon to compensate in any desired amount forsaid fluid force changes and disposed within said aperture to comprise amovable portion of a wall of said chamber, means to mount said pressuresensitive member to position same within said aperture to provide apredetermined clearance space between its perimetrical surface and theadjacent surface forming said aperture, said mounting means includingsubstantially frictionless swingable means imparting rigidity in allexcept one direction and acting to support said pressure sensitivemember and to maintain said perimetrical clearance in all operativepositions of said member for substantially frictionless movements insaid one direction, and pressure-regulator means operatively associatedwith said control means to regulate said source pressure atpredetermined values varying as a function of the position of saidcontrol means and tending to correspondingly vary said pressurecontrolled by said valve member in a direction tending to reverse themovement of said control means, said pressure regulator means includingmeans to maintain said source pressure under all conditions at one saidpredetermined value corresponding to one definite position of saidcontrol means and at another said predetermined value corresponding toanother definite position of said control means under all conditions,and so on.

6. In a self-regulating control mechanism for automatically controllinga variable condition the combination of, control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of pressure fluid to produce a flow of fluid therethrough andcommunicating with said pressure responsive member on one side thereof,valve means in said circuit for controlling pressure therein acting onlyon said one side of said pressure responsive member for effectingregulating movements thereof, first variable force biasing meansopposing the forces of said pressure responsive member produced by saidlast-named pressure acting thereon, sensing means responsive to changesin the controlled condition to produce forces varying as a functionthereof and acting on said valve means to effect movements thereof forcausing said controlled-conditionregulating movements of said pressureresponsive member and said control means, second variable force biasingmeans acting on said valve means with a force varying as a function ofthe position thereof for establishing the operating position of saidvalve means to establish the desired value of said controlled condition,pressure-regulator means operatively associated with said control meansto vary the magnitude of said sourcepressure as a function of theposition of said control means, said pressure-regulator means includinga diaphragm exposed to said source pressure, third biasing means actingon said diaphragm, second valve means in said circuit between saidsource pressure and said firstnamed valve means and operated by saiddiaphragm to correspondingly vary said pressure controlled by saidfirst-named valve means as a function of the position of said controlmeans and in a direction tending to reverse the movement of said controlmeans during stable automatic regulation thereof, saidpressure-regulator means including means operatively connected to saidcontrol means for causing said second valve means to provide saidlast-named pressure variation.

7. In a. self-regulating control mechanism for automatically controllinga variable condition the combination of, control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of pressure fluid to produce a flow of fluid therethrough andcommunicating with said pressure responsive member on one side thereof,valve means in said circuit for controlling pressure therein acting onlyon said one side of said pressure responsive member for effectingregulating movements thereof, first variable force biasing meansopposing the forces of said pressure responsive member produced by saidlast-named pressure acting thereon, sensing means responsive to changesin the controlled condition to produce forces varying as a functionthereof and acting on said valve means to effect movements thereof forcausing said controlled-condition-regulating movements of said pressureresponsive member and said control means, second variable force biasingmeans acting on. said valve means with a force varying as a functionthereof for establishing the operating position of said valve means toestablish the desired value of said controlled condition,pressure-controlling means including pressure regulator meansoperatively associated with said control means to vary the magnitude ofsaid source-pressure as a function of the movement of said control meansand tending to correspondingly vary said pressure controlled by saidvalve means in a direction tending to reverse the movement of saidpressure responsive member and said control means, re-set means disposedto operatively act on said valve means with a re-set force varying as afunction of the position of said control means, and delay meansoperatively connected to said reset means and said control means fordelaying a change in the amount of said re-set force in response to achange in the position of said control means, whereby the controlmechanism is stable at any desired variation of said controlledcondition.

8. The combination of means defined in claim 4, and re-set meansdisposed to operatively act on said valve means with a re-set forcevarying as a function of the position of said control means, and delaymeans operatively connected to said re-set means and said control meansfor delaying a change in the amount of said re-set force in response toa change in the position of said control means, whereby the controlmechanism provides stable operation at any desired variation of saidcontrolled condition.

9. In a self-regulating control mechanism for automatically controllinga variable condition the combination of, control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of pressure fluid to produce a flow of fluid therethrough andcommunicating with said pressure responsive member on one side thereof,valve means including a movable valve member in said circuit forcontrolling pressure therein acting only on said one side of saidpressure responsive member for effecting regulating movements thereof,said valve member in relation to other elements of said valve meansbeing adapted to produce modulated pressures acting on said pressureresponsive member to effect movements thereof as a function 13 of theposition of said valve member, first biasing means acting on saidpressure responsive member with a force varying as a function of theposition thereof to oppose the forces produced thereon by saidlast-named pressure, sensing means responsive to changes in thecontrolled condition to produce forces varying as a function thereof andacting on said valve means to effect movements thereof for causing saidcontrolled-condition-regulating movements of said pressure responsivemember and said control means, second variable force biasing meansacting on said valve means With a force varying as a funclate saidsource-pressure at predetermined values varying t as a function of theposition of said control means and tending to correspondingly vary saidpressure controlled by said valve means in a direction tending toreverse the movement of said control means, said pressure-regulatormeans including means to maintain said source pressure under allconditions at one said predetermined value corresponding to one definiteposition of said control means and at another said predetermined valuecorresponding to another definite position of said control means underall conditions, and so on, said valve member having a portion exposed tosaid varying source pressure and tending to be affected by changes influid force produced on said valve portion by variation in said sourcepressure, a fiuid chamber having an aperture therein, and a pressuresensitive member subjected to said source pressure and operativelyassociated with said valve member to apply forces acting thereon tocompensate in any desired amount for said fluid force changes anddisposed Within said aperture to comprise a movable portion of a Wall ofsaid chamber.

10. In a self-regulating control mechanism for automatically controllinga variable condition, the combination of; control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of varying fluid pressure to produce a flow of fluid therethroughand communicating with said pressure responsive member, a restriction insaid circuit exposed to said varying source pressure, valve meansincluding a movable valve member in said circuit cooperating with saidrestriction for controlling pressure therein acting on said pressureresponsive member for effecting movements thereof, said valve memberhaving a portion exposed to said varying source pressure and tending tobe affected by changes in fluid force produced on said valve portion byvariation in said source pressure, sensing means responsive to changesin said controlled condition and providing forces acting on said valvemember to effect movements thereof for producingcontrolled-condition-regulating movements of said pressure responsivemember and said control means, a fiuid chamber having an aperturetherein, a pressure sensitive member exposed to said source pressure andoperatively connected to said valve member to apply forces actingthereon to compensate in any desired amount for said fluid force changesand disposed Within said aperture to comprise a movable portion of aWall of said chamber, means to mount said pressure sensitive member toposition same within said aperture to provide a predetermined clearancespace between its perimetrical surface and the adjacent surface formingsaid aperture, said mounting means including substantially frictionlessswingable leaf spring means imparting rigidity in all except onedirection and acting to support said pressure sensitive member and tomaintain said perimetrical clearance in all operative positions of saidmember for substantially frictionless movements in said one direction,said leaf spring means also acting to support said movable valve memberfor substantially frictionless movements in said one direction bymaintaining said supported valve member suspended within the fluidcontrolled thereby completely free of surface contact other than fluidcontact during operational movements thereof, and pressureregulatormeans operatively associated with said control means to regulate saidsource pressure at predetermined values varying as a function of theposition of said control means and tending to correspondingly vary saidpressure controlled by said valve member in a direction tending toreverse the movement of said control means, said pressure regulatormeans including means to maintain said source pressure under allconditions at one said predetermined value corresponding to one definiteposition of said control means and at another said predetermined valuecorresponding to another definite position of said control means underall conditions, and so on.

11. In a self-regulating control mechanism for automatically controllinga variable condition the combination of; control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of pressure fluid to produce a flow of fluid therethrough andcommunicating with said pressure responsive member on one side thereof,valve means including a movable valve member in said circuit forcontrolling pressure therein acting only on said one side of saidpressure responsive member for effecting regulating movements thereof,said valve member in relation to other elements of said valve meansbeing adapted to produce modulated pressures acting on said pressureresponsive member to effect movements thereof as a function of theposition of said valve member, first biasing means acting on saidpressure responsive member with a force varying as a function of theposition thereof to oppose the forces produced thereon by saidlast-named pressure, sensing means responsive to changes in thecontrolled condition to produce forces varying as a function thereof andacting on said valve means to effect movements thereof for causing saidcontrolled-condition-regulating movements of said pressure responsivemember and said control means, second variable force biasing meansacting on said valve means with a force varying as a function of theposition thereof for establishing the operating position of said valvemeans to establish the desired value of said controlled condition, andpressure-regulator means including pressure responsive means exposed tosaid source pressure and operatively associated With said control meansto vary the magnitude of said source-pressure as a function of theposition of said control means and tending to correspondingly vary saidpressure controlled by said valve means in a direction tending toreverse the movement of said control means, said pressure regulatormeans including means operatively connected to said control means forcausing said functional pressure variation.

12. In a self-regulating control mechanism for automatically controllinga variable condition the combination of; control means to regulate saidcontrolled condition, a pressure responsive member operatively connectedto said control means for actuation thereof, a fluid circuit having asource of pressure fluid to produce a flow of fluid therethrough andcommunicating with said pressure responsive member on one side thereof,valve means in said circuit for controlling pressure therein acting onlyon said one side of said pressure responsive member for effectingregulating movements thereof, said valve means being adapted to producemodulated pressures acting on said pressure responsive member to effectsaid movements thereof as a function of the position of said valvemeans, first variable force biasing means opposing the forces of saidpressure responsive member produced by said lastnamed pressure actingthereon, sensing means responsive to changes in the controlled conditionto produce forces varying as a function thereof and acting on said valvemeans to effect movements thereof for causing said con- 15trolled-condition-regulating movements of said pressure responsivemember and said control means, second variable force biasing meansacting on said valve means with a force varying as a function of theposition thereof for establishing the operating position of said valvemeans to establish the desired value of said controlled condition,pressure-regulator means operatively associated with said control meansto regulate said source-pressure at predetermined values varying as afunction of the position of said control means and tending tocorrespondingly vary said pressure controlled by said valve means in adirection tending to reverse the movement of said control means, saidpressure regulator means including means to maintain said sourcepressure under all conditions at one said predetermined valuecorresponding to one definite position of said control means and atanother said predetermined value corresponding to another definiteposition of said control means under all conditions, and so on, re-setmeans disposed to operatively act on said valve means with a re-setforce varying as a function of the position of said control means, delayspring means operatively connected to said control means to produceforces varying as a function of the position thereof, and fluid delaymeans operatively connected between said re-set means and said delayspring means for transmitting said forces of said delay spring means tosaid reset means after and lagging behind transient movements of saidcontrol means, for delaying a change in the amount of said re-set forcein response to a change in the position of said control means.

No references cited.

CLARENCE R. GORDON, Primary Examiner.

1. IN A SELF-REGULATING CONTROL MECHANISM FOR AUTOMATICALLY CONTROLLINGA VARIABLE CONDITION THE COMBINATION OF, CONTROL MEANS TO REGULATE SAIDCONTROLLED CONDITION, A PRESSURE RESPONSIVE MEMBER OPERATIVELY CONNECTEDTO SAID CONTROL MEANS FOR ACTUATION THEREOF, A FLUID CIRCUIT HAVING ASOURCE OF PRESSURE FLUID TO PRODUCE A FLOW OF FLUID THERETHROUGH ANDCOMMUNICATING WITH SAID PRESSURE RESPONSIVE MEMBER, VALVE MEANS IN SAIDCIRCUIT FOR CONTROLLING PRESSURE THEREIN ACTING ON SAID PRESSURERESPONSIVE MEMBER FOR EFFECTING REGULATING MOVEMENTS THEREOF, SENSINGMEANS RESPONSIVE TO CHANGES IN THE CONTROLLED CONDITION TO PRODUCEFORCES VARYING AS A FUNCTION THEREOF AND ACTING ON SAID VALVE MEANS TOEFFECT MOVEMENTS THEREOF FOR CAUSING SAIDCONTROLLED-CONDITION-REGULATING MOVEMENTS OF SAID PRESSURE RESPONSIVEMEMBER AND SAID CONTROL MEANS, AND PRESSURE-CONTROLLING MEANS INCLUDINGPRESSURE REGULATOR MEANS OPERATIVELY ASSOCIATED WITH SAID CONTROL MEANSTO VARY THE MAGNITUDE OF SAID SOURCE-PRESSURE AS A FUNCTION OF THEMOVEMENT OF SAID CONTROL MEANS AND TENDING TO CORRESPONDINGLY VARY SAIDPRESSURE CONTROLLED BY SAID VALVE MEANS IN A DIRECTION TENDING TOREVERSE THE MOVEMENT OF SAID PRESSURE RESPONSIVE MEMBER AND SAID CONTROLMEANS.